The present invention generally relates to water purification systems and methods and, more specifically, to a filter assembly and methods using a plurality of cartridges coupled with a water distributing manifold for directing water in a serial or parallel manner through each cartridge.
Water purification systems are used to provide high quality reagent grade water for various applications, including scientific testing and analysis applications. Many of these applications require that the total organic carbon content of the water be on the order of 10 parts per billion or less. They may further require a resistivity of up to 18.2 megohm-cm. ASTM Type I water is the highest purity and is used for high performance liquid chromography, atomic absorption spectrometry, tissue culture, etc. Type II water is less pure and may be used for hematological, serological, and microbiological procedures. Type III water is suitable for general laboratory qualitative analyses, such as urinalysis, parasitology and histological procedures. Two prior systems for purifying water are disclosed in U.S. Pat. Nos. 5,397,468 and 5,399,263, each assigned to the assignee of the present invention. The disclosure of each of these patents is hereby incorporated herein by reference.
Typical water purifiers have a cartridge assembly comprised of a plurality of purification cartridges. Each cartridge contains a purification media, such as a mass of resin beads, for purifying the water in accordance with the application requirements. The water flows through each cartridge in a serial manner. The water exits the final cartridge of the cartridge assembly in a purified condition and is dispensed as needed by the user.
Various manners of connecting the cartridges have been used in the past, including the use of separate fittings and fluid lines between the cartridges and the use of integral manifolds. Assemblies utilizing integral manifolds are not easily modifiable to accommodate a different cartridge configuration or and number of cartridges. If a different cartridge configuration or number of cartridges is desired or necessary, the entire assembly, including the manifold and cartridges is typically modified and retooled for manufacturing purposes. On the other hand, the use of separate fittings and fluid lines between the cartridges makes replacement difficult.
Another disadvantage of prior water purification systems, especially those utilizing integral manifolds, is that the water flow path may not be easily diverted from the cartridge assembly to an auxiliary processing device and back to the cartridge assembly. For example, an ultraviolet (UV) chamber may be used as an auxiliary processing device to reduce organics in the water. Ideally, the water is then returned to the cartridge assembly for a final polishing, or purification, through a final cartridge. Some systems have been configured such that the water does not pass through a final cartridge after going through the UV chamber. This can cause resistivity problems with the water dispensed from the system since any ionic impurities, such as oxidized organics, are not filtered out before dispensing the water. Another option used in prior systems has been to pass the water through the cartridge assembly entirely, and then pass the water through a UV chamber. A separate cartridge, which is not part of the cartridge assembly of the water purification system, is then used to polish the water before it is dispensed by the user. This makes cartridge replacement more difficult, however, since the user must replace both the cartridge assembly and a separate final filter or cartridge.
In view of the above problems noted in the art, as well as other problems and concerns, it would be desirable to provide a water purification system and methods utilizing a cartridge assembly which may be more easily reconfigured and which allows an auxiliary processing device, such as a UV chamber or another device, to be fluidly coupled with the cartridge assembly while also allowing a final polishing of the water flowing through the system.
The present invention therefore generally provides a water purifying apparatus and, more specifically, a filter assembly having various features for facilitating easier and more efficient manufacturing, set up and use of the apparatus. In one general aspect, the filter assembly comprises a plurality of cartridges affixed to one another with each cartridge having first and second ends. Each cartridge further includes a sidewall extending between the first and second ends and an interior volume. A filtering medium is contained within the interior volume for at least assisting in filtering water flowing through the interior volume. A plurality of end caps respectively connect with the first ends of the plurality of cartridges and each end cap includes a water inlet and a water outlet. A manifold couples to the water inlets and water outlets of the plurality of end caps to connect the cartridges for fluid communication such that the water flows through the filtering medium within the interior volume of one cartridge, through the manifold, preferably to the filtering medium within the interior volume of another cartridge. Cartridges may also or alternatively be fluidly coupled in a parallel manner. The manifold further includes a water inlet for directing water into the cartridges, a water outlet for directing water out of the cartridges and a pair of auxiliary ports. The auxiliary ports include an auxiliary output port for directing water from the cartridge assembly to an auxiliary processing device and an auxiliary input port for directing the water from the auxiliary processing device to one of the water inlets associated with an end cap. This aspect of the invention allows the auxiliary ports to be optionally used, for example, to direct water from the cartridge assembly to a UV chamber or other water processing device, and then back into the cartridge assembly for at least a final polishing operation to remove further organics or other contaminants. If such an auxiliary processing device is not necessary for any given application, the auxiliary output port may be fluidly coupled with the auxiliary input port to maintain the fluid coupling between the cartridges.
As another aspect of the invention, the manifold is removably coupled with the water inlets and water outlets of the plurality of end caps. Since the manifold is removable, a different configuration of the same cartridges and/or a different number of cartridges may be coupled in fluid communication, depending on the needs of any particular application, simply by providing a correspondingly configured manifold. Unlike past purifying systems having integral manifolds, only the removable manifold of the present invention is replaced to allow the reconfiguration. As another related aspect, which also allows for easier reconfiguration of the cartridges, the water inlet and water outlet associated with each end cap extends generally parallel to the longitudinal axis of the cartridge. Unlike prior cartridges, which have inlets and outlets extending generally transverse or perpendicular to the longitudinal axis of the cartridge, or have an inlet and outlet respectively located at opposite ends of the cartridge, this allows the manifold to be placed and fluidly coupled directly on top of the plurality of cartridges. This aspect further facilitates easy fluid connection and reconfiguration of the cartridges.
As another aspect of the invention, the cartridge preferably includes an outer tubular member having first and second ends and an interior volume. A first end cap is secured to the first end of the outer tubular member and includes a water inlet leading to the interior volume and a water outlet. A second end cap is secured to the second end of the outer tubular member. An inner tubular member includes a first end connected in a sliding manner to the first end cap and a second end rigidly affixed to the second end cap. The first end of the inner tubular member is coupled in fluid communication with the water outlet and the second end is coupled in fluid communication with the interior volume. Constructing the cartridge in this manner allows for more efficient manufacturing, while also facilitating the preferred flow of water through the interior volume of the outer tubular member and the purifying medium contained therein and outward flow through the inner tubular member.
These and other objectives, advantages and features of the invention will become more readily apparent to those of ordinary skill in the art upon review of the following detailed description of the preferred embodiments, taken in conjunction with the accompanying drawings.